3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array1 = [1, 3, 3, 3, 4, 7, 7, 8, 8]; $array2 = [0, 3, 3, 4, 4, 9, 9, 9]; $counts1 = array_count_values($array1); $counts2 = array_count_values($array2); $result = []; foreach ($counts1 + $counts2 as $num => $cnt) { array_push( $result, ...array_fill( 0, max($counts1[$num] ?? 0, $counts2[$num] ?? 0), $num ) ); } var_export($result);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14
array ( 0 => 1, 1 => 3, 2 => 3, 3 => 3, 4 => 4, 5 => 4, 6 => 7, 7 => 7, 8 => 8, 9 => 8, 10 => 0, 11 => 9, 12 => 9, 13 => 9, )

preferences:
109.87 ms | 407 KiB | 5 Q